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Total 321 documents matching your query.

181. Re: [Amps] Soft Tubes? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Mon, 28 Mar 2005 18:52:50 -0800
Good point, Gerald. A more likely explanation for the low efficiency on 10 meters might be a combination of higher tank circuit losses and wattmeter calibration error. Still, I hear people talking ab
/archives//html/Amps/2005-03/msg00651.html (7,325 bytes)

182. [Amps] 1296 KW Amp (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 14 Apr 2005 21:29:20 -0700
Anybody make a commercially available KW amplifier that covers 1296 MHz? Thanks, Mike, W4EF................ _______________________________________________ Amps mailing list Amps@contesting.com http:
/archives//html/Amps/2005-04/msg00290.html (6,292 bytes)

183. Re: [Amps] Skin Effect and Wire Current Capacity at HF (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 14 Apr 2005 23:49:34 -0700
The amount of heating you will see in your inductor will depend on the ratio of the loaded vs. unloaded Q of the inductor. In circuits like TVI low-pass filters, the loaded Q is very low (something l
/archives//html/Amps/2005-04/msg00293.html (9,617 bytes)

184. Re: [Amps] grid dip meters (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 17 Apr 2005 11:55:21 -0700
Just a word of caution, Harry. I'm told the MFJ-259 makes a lousy grid dipmeter. In a normal dipmeter the coils are part of the oscillator tank circuit so you can get tight coupling between the devic
/archives//html/Amps/2005-04/msg00338.html (8,047 bytes)

185. Re: [Amps] NASA Workmanship Standards (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 28 Jul 2005 21:17:15 -0700
Not sure where you heard that, Hal. I can't imagine a rad-hard flight qualified IC of any kind costing $1.79. Maybe a flight machine screw, but not a rad-hard IC. I know a retired propulsion engineer
/archives//html/Amps/2005-07/msg00354.html (9,739 bytes)

186. Re: [Amps] FW: AMERITRON AL-1500 ???? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 7 Aug 2005 19:32:17 -0700
Rich, You are making an apples to oranges comparison. The issue isn't the current carrying capability of the 8877 grid, it is the power dissipation of the grid. A capacitor has a power factor of ~0.0
/archives//html/Amps/2005-08/msg00268.html (8,733 bytes)

187. Re: [Amps] FW: AMERITRON AL-1500 ???? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 7 Aug 2005 20:47:06 -0700
Yes, of course, Rich, but the ESR is not what is entirely responsible for grid dissipipation due to grid current flowing under conditions of excessive drive. If it were, the grid drive voltage term w
/archives//html/Amps/2005-08/msg00272.html (9,904 bytes)

188. Re: [Amps] FW: AMERITRON AL-1500 ???? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 7 Aug 2005 21:16:05 -0700
Well....yes..... but the argument is still the same. And if grid dissipation were a function simply of conductor ESR, why would even 350mA let alone 100mA be a big deal for a #16 AWG equivalent condu
/archives//html/Amps/2005-08/msg00274.html (10,190 bytes)

189. [Amps] RF Parts OEM 3-500ZG's (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 7 Aug 2005 21:54:52 -0700
I just bought a used Ten-Tec Centurion on behalf of a friend. We both were under the mis-informed belief that it would be equipped with Eimac 3-500ZG's. Instead it has a matched pair of RF Parts bran
/archives//html/Amps/2005-08/msg00275.html (6,494 bytes)

190. Re: [Amps] RF Parts OEM 3-500ZG's (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Mon, 8 Aug 2005 21:13:55 -0700
Thanks to everyone who replied to my inquiry about the RF Parts RFP 3-500ZG's. Your comments were all very helpful to me. There was a pretty big consensus that among those who responded that the RFP
/archives//html/Amps/2005-08/msg00313.html (9,454 bytes)

191. Re: [Amps] Grid Current Advice (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Tue, 16 Aug 2005 00:09:53 -0700
If you assume an input impedance of 58 ohms (115 ohms/tube divided by 2 for the pair) and 100 watts of drive power, that works out to around 76 volts RMS grid-to-cathode potential. With a 40W maximum
/archives//html/Amps/2005-08/msg00545.html (9,437 bytes)

192. [Amps] Oil Filled Capacitors (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 21 Aug 2005 23:12:17 -0700
A friend of mine is building an new amplifier and is looking for a couple of oil filled HV capacitors for the power supply He wants something in the range of 8 to 10uF at 8 to 10KV. If you have some
/archives//html/Amps/2005-08/msg00651.html (6,360 bytes)

193. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 25 Aug 2005 10:20:36 -0700
It suspect that they are talking about the Rp component as it relates to the ohmic losses (read self-heating) of the choke. For Xp = 3000 ohms, Rp would be well in excess of 200,000 ohms even for a m
/archives//html/Amps/2005-08/msg00675.html (8,884 bytes)

194. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 25 Aug 2005 12:44:18 -0700
It would appear that you are correct, Roy. I just looked at Bill Orr's info on plate choke design (Radio Handbook 23rd edition, page 12-6). While I knew that series resonant points needed to be avoid
/archives//html/Amps/2005-08/msg00679.html (9,336 bytes)

195. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 25 Aug 2005 16:15:38 -0700
At the risk of sticking my foot in my mouth again, R generally doesn't effect the resonant frequency of an RLC circuit appreciably provided that the Q is reasonably high. On the other hand, a plate c
/archives//html/Amps/2005-08/msg00682.html (8,662 bytes)

196. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 25 Aug 2005 19:15:26 -0700
Yes, I understand that, Jim, but I was having a hard time believing that you could get away with deQing a choke enough to shift the resonant frequency significantly without turning it into a firework
/archives//html/Amps/2005-08/msg00684.html (9,381 bytes)

197. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 25 Aug 2005 22:48:00 -0700
Well before today, Tomm, I would have thought the same, but after looking at Orr's Handbook, I am beginning to think otherwise. For instance Orr describes an "HF Radio Frequency Choke for Power Ampli
/archives//html/Amps/2005-08/msg00686.html (10,941 bytes)

198. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Fri, 26 Aug 2005 18:22:05 -0700
I just wanted to see if there was a parallel resonance at work in the working operating range (as opposed to a nearly pure inductance). Presumeably any parallel resonance will be there regardless of
/archives//html/Amps/2005-08/msg00712.html (9,712 bytes)

199. Re: [Amps] plate choke (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sat, 27 Aug 2005 13:32:17 -0700
What answer? I still don't know if typical single-layer plate chokes rely on a parallel resonance to acheive suffcient low-end choking impedance; I still don't know if the impedance vs. frequency cu
/archives//html/Amps/2005-08/msg00728.html (10,244 bytes)

200. Re: [Amps] Oil Filled Capacitors (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sat, 27 Aug 2005 20:48:51 -0700
Thanks to all who responded to my inquiry on oil filled caps earlier this week. I have forwarded this information to my friend. He will contact you directly if he is interested. 73 de Mike, W4EF.....
/archives//html/Amps/2005-08/msg00735.html (7,231 bytes)

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